摘要:

Chemometric methods to analyze spectroscopic data without using reference spectra are discussed. The data are first decomposed into principal components, and the number of contributing species is determined by statistical tests. The principal components are then rotated to produce spectroscopic responses and concentration profiles of the chemical species present. Samples that vary in a physical property like pH, total concentration, temperature, or ionic strength, are analyzed by regular 1-dimensional spectroscopy assuming that the components are in chemical equilibrium. Samples containing noninteracting compounds are analyzed by multidimensional spectroscopy, and the principal components are calculated by Procrustes rotation. Several applications of the two approaches on absorption and fluorescence data are presented.

ISSN:1040-8347    

DOI:10.1080/10408349891199275

出版商:TAYLOR & FRANCIS    

年代:1999

数据来源: Taylor

摘要:

Developments in nonconventional sample introduction in capillary electrophoresis have focused on the possibility of forcing the sample stream to pass the separation capillary inlet. The advantages of such input devices are the absence of a voltage rise/drop time during sampling, ease of operation because no vial manipulations are involved, and ease of automation and computerization. However, besides these the main advantage of such input devices seems to be the fact that they facilitate easy, multiple input from a single sample vial. This opens the possibility of monitoring the concentration changes taking part in inside the vessel — an important task for — analytical biotechnology.This article describes some possible designs of CE nonconventional samplers and discusses applications of such samplers in sample preparation, in coupling CE with flow injection analysis (FIA) and HPLC, in multiple input experiments (with or without stacking) for reduction of detection limits and for monitoring of reaction kinetics.

ISSN:1040-8347    

DOI:10.1080/10408349891199284

出版商:TAYLOR & FRANCIS    

年代:1999

数据来源: Taylor